# Preface

Once upon a time, Unix came with only a few standard utilities, and if you were lucky, it included a C compiler. When setting up a new Unix system, you'd have to crawl the Net looking for important software: Perl, gcc, bison, flex, less, Emacs, and other utilities and languages. That was a lot of software to download through a 28.8 kbps modem. These days, Unix distributions come with much more, and it seems like more and more users are gaining access to a wide-open pipe.

Free Linux distributions pack most of the GNU tools onto a CD-ROM, and now commercial Unix systems are catching up. IRIX includes a big selection of GNU utilities, Solaris comes with a companion CD of free software, and just about every flavor of Unix (including Mac OS X) now includes Perl. Mac OS X comes with many tools, most of which are open source and complement the tools associated with Unix.

This book serves as a bridge for Unix developers and system administrators who've been lured to Mac OS X because of its Unix roots. When you first launch the Terminal application, you'll find yourself at home in a Unix shell, but like Apple's credo--"Think Different"--you'll soon find yourself doing things a little differently. Some of the standard Unix utilities you've grown accustomed to may not be there, /etc/passwd and /etc/group have been supplanted with something called NetInfo, and when it comes to developing applications, you'll find that things like library linking and compiling have a few new twists to them.

Despite all the beauty of Mac OS X's Aqua interface, you'll find that a few things are different on the Unix side. But rest assured, they're easy to deal with if you know what to do. This book is your survival guide for taming the Unix side of Mac OS X.

## 0.1. Audience for This Book

This book is aimed at Unix developers, a category that includes programmers who switched to Linux from a non-Unix platform, web developers who spend most of their time in ~/public_html over an ssh connection, and experienced Unix hackers. In catering to such a broad audience, we chose to include some material that advanced users might consider basic. However, this choice makes the book accessible to all Unix programmers who switch to Mac OS X as their operating system of choice, whether they have been using Unix for one year or ten. If you are coming to Mac OS X with no Unix background, we suggest that you start with Learning Unix for Mac OS X (O'Reilly & Associates, Inc.) to get up to speed with the very basics.

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